Abstract: In order to achieve large-scale pyroelectric infrared focal plane array (IRFPA) detector with high resolution, the readout circuit with multi-channel parallel output was designed. Based on the pyroelectric IRFPA detector of multiple-output and the pyroelectric detecting timing requirements, the system of mosaic imaging acquisition was designed. The external driving signals were used to control the trigger and sampling clock of acquisition card, and a chopper synchronizing signal was used to judge the bright field and dark field signal of the pyroelectric detector. The system was constructed with PC-DAQ virtual instrument system to acquire multi-channel parallel image, judge the bright and dark field for differential processing on each channel, and display a whole image after mosaic processing on software platform. The experimental image acquisition of the pyroelectric readout circuit with 160 120 two-channels readout and 320 120 four-channels readout were taken and the output signal waveform and image were showed after connecting the two-channels and four-channels signals. Compared with the single channel readout structure of the same scale detector, the readout speed of two channels structure doubles, and the four channels readout speed improves 3 times.